7.1 - RHSA-2012:1580

Problem Description:

Updated kernel packages that fix multiple security issues, numerous bugs and add one enhancement are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Desktop (v. 6) - i386, noarch, x86_64 Red Hat Enterprise Linux Desktop Optional (v. 6) - i386, x86_64 Red Hat Enterprise Linux HPC Node (v. 6) - noarch, x86_64 Red Hat Enterprise Linux HPC Node Optional (v. 6) - x86_64 Red Hat Enterprise Linux Server (v. 6) - i386, noarch, ppc64, s390x, x86_64 Red Hat Enterprise Linux Server Optional (v. 6) - i386, ppc64, s390x, x86_64 Red Hat Enterprise Linux Workstation (v. 6) - i386, noarch, x86_64 Red Hat Enterprise Linux Workstation Optional (v. 6) - i386, x86_64

3. Description:

The kernel packages contain the Linux kernel, the core of any Linux operating system.

This update fixes the following security issues:

* It was found that the RHSA-2012:0862 update did not correctly fix the CVE-2011-4131 issue. A malicious Network File System version 4 (NFSv4) server could return a crafted reply to a GETACL request, causing a denial of service on the client. (CVE-2012-2375, Moderate)

* A divide-by-zero flaw was found in the TCP Illinois congestion control algorithm implementation in the Linux kernel. If the TCP Illinois congestion control algorithm were in use (the sysctl net.ipv4.tcp_congestion_control variable set to "illinois"), a local, unprivileged user could trigger this flaw and cause a denial of service. (CVE-2012-4565, Moderate)

* A NULL pointer dereference flaw was found in the way a new node's hot added memory was propagated to other nodes' zonelists. By utilizing this newly added memory from one of the remaining nodes, a local, unprivileged user could use this flaw to cause a denial of service. (CVE-2012-5517, Moderate)

* It was found that the initial release of Red Hat Enterprise Linux 6 did not correctly fix the CVE-2009-4307 issue, a divide-by-zero flaw in the ext4 file system code. A local, unprivileged user with the ability to mount an ext4 file system could use this flaw to cause a denial of service. (CVE-2012-2100, Low)

* A flaw was found in the way the Linux kernel's IPv6 implementation handled overlapping, fragmented IPv6 packets. A remote attacker could potentially use this flaw to bypass protection mechanisms (such as a firewall or intrusion detection system (IDS)) when sending network packets to a target system. (CVE-2012-4444, Low)

Red Hat would like to thank Antonios Atlasis working with Beyond Security's SecuriTeam Secure Disclosure program and Loganaden Velvindron of AFRINIC for reporting CVE-2012-4444. The CVE-2012-2375 issue was discovered by Jian Li of Red Hat, and CVE-2012-4565 was discovered by Rodrigo Freire of Red Hat.

This update also fixes numerous bugs and adds one enhancement. Space precludes documenting all of these changes in this advisory. Documentation for these changes will be available shortly from the Red Hat Enterprise Linux 6.3 Technical Notes document linked to in the References section.

Users should upgrade to these updated packages, which contain backported patches to correct these issues, fix these bugs and add the enhancement noted in the Technical Notes. The system must be rebooted for this update to take effect.

4. Solution:

Before applying this update, make sure all previously-released errata relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to use the Red Hat Network to apply this update are available at https://access.redhat.com/knowledge/articles/11258

To install kernel packages manually, use "rpm -ivh [package]". Do not use "rpm -Uvh" as that will remove the running kernel binaries from your system. You may use "rpm -e" to remove old kernels after determining that the new kernel functions properly on your system.

5. Bugs fixed (http://bugzilla.redhat.com/):

809687 - CVE-2012-2100 kernel: ext4: fix inconsistency in ext4_fill_flex_info() 822869 - CVE-2012-2375 kernel: incomplete fix for CVE-2011-4131 871848 - CVE-2012-4565 kernel: net: divide by zero in tcp algorithm illinois 874835 - CVE-2012-4444 kernel: net: acceptation of overlapping ipv6 fragments 875374 - CVE-2012-5517 kernel: mm/hotplug: failure in propagating hot-added memory to other nodes 876549 - drm cherry-pick patch from upstream bug for 6.4 [rhel-6.3.z]